1. Field of the Invention
This invention pertains to processing bulk food material, and more particularly to apparatus that operates with minimal vibrations to form individual food items from bulk food material.
2. Description of the Prior Art
Various equipment has been developed to produce individual items of food products from a bulk supply. For example, machines that produce individual patties of ground meat are well known and in widespread use. Similar machines are used to produce nuggets of whole muscle meat. U.S. Pat. Nos. 4,054,967 and 4,097,961 show typical prior machines that form patties from ground meat. U.S. Pat. No. 4,872,241 describes a prior machine for making nuggets from whole muscle meat.
Briefly by way of explanation, a supply of bulk food material is forced under pressure from a hopper through one or more fill slots in a fill plate into individual cavities in a mold plate at a fill position. On the opposite side of the mold plate as the fill plate is a breather plate. Air and some juices flow through small holes and into a channel in the breather plate as the mold plate cavities are filled. The breather plate channel communicates with a vent hole through the mold plate. In turn, the mold plate vent hole communicates with an opening in the fill plate. A duct connects the fill plate opening with the food hopper.
After the mold plate cavities have been filled, the pressure on the bulk food product is reduced. The mold plate slides longitudinally in a forward stroke such that the cavities lose communication with the fill plate fill slots. The mold plate slides to an eject position where the food material is ejected from the cavities in the form of individual patties. The mold plate then slides back to the fill position, and the cycle repeats.
At the start of the mold plate forward stroke, food product continues to fill the cavities. Accordingly, some air continues to be displaced from the cavities to the breather plate. In machines with a mold plate having only one transverse row of cavities, there is an uninterrupted communication between the breather plate and the atmosphere as long as the cavities are in communication with the fill plate fill slots.
A problem arises with mold plates having a second row of cavities. When the mold plate slides in the forward stroke, the second row of cavities comes into communication with the fill plate fill slots and are filled while the mold plate is moving. However, by the time the second row of cavities has reached the fill slot, the mold plate vent hole has lost communication with the breather plate and fill plate grooves. Consequently, the air and juices displaced from the cavities become trapped in the breather plate. The pressure of the trapped air forces the mold plate against the fill plate, causing frictional resistance to mold plate sliding. The result is detrimental vibrations and chatter of the machine. The friction problem is especially acute on machines that have more than two longitudinally spaced rows of cavities.
Thus, a need exists for eliminating the lateral force on the mold plate during reciprocation.